JP2000344398A - Sheet member conveying device and image forming device comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the workability and the reliability by comprising a drop prevention mechanism capable of being retreated for not disturbing the conveying of a sheet member when loading surface is closed, and preventing the sheet member from being dropped from the loading surface in accompany with the opening motion of the plate when the loading surface is opened. SOLUTION: A drop prevention member 137 is concealed by a lower roller 14X in a horizontal position for conveying a document, and the document is fed by rollers 14Z, 14X. When a 13 starts its upward rotation, a member to be contacted 135 is smoothly rotated in a state that it is gradually contacted with an inclined part of an upper surface of a contact member in the direction of arrow B by the energization force of a spring 134. A rotary shaft is rotated in the direction of arrow B by the rotation of the member to be contacted 135, and the drop prevention member 137 fixed to the rotary shaft is also rotated in the direction of arrow B by the rotation of the rotary shaft. The drop prevention member 137 is rotated to be projected from a position to act on the document from a state that it is accomodated in an accomodating part. Whereby the document can be prevented from being dropped from an end part of the loading surface 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document transport function for transporting a document placed on an image forming apparatus to a document image reading section provided on the upper surface of the image forming apparatus. In the sheet member conveying device having
The present invention relates to a fall prevention mechanism for preventing a sheet member from falling from a mounting table of the sheet member when the sheet member is opened.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a facsimile or a copying machine, an image forming apparatus in which a sheet member conveying device is disposed above an image forming apparatus main body is generally provided. This image forming apparatus includes a main body 600 as shown in FIG.
, A sheet member transport device 620 disposed on the right side of the sheet member mounting table 610, a scanner 630 disposed below the sheet member mounting table 610, and the scanner. An optical unit 640 disposed below the optical unit 630, and an image of the sheet member which is disposed below the optical unit 640 and is exposed to the laser light output from the optical unit 640 is visualized into a toner image. An image forming section 650 having a photosensitive drum 651 for transferring to a transfer paper;
50, a transfer paper feeding unit 660 having a paper feed cassette 661, a fixing unit 670 provided downstream of the transfer paper feeding unit 660, and the fixing unit 6
A transfer paper discharge unit 680 is provided downstream of the transfer paper 70. Further, the sheet member conveying device feeds and conveys the sheet originals stacked on the sheet member mounting table one by one toward an image reading portion of the image forming apparatus main body by a sheet feeding means such as a sheet feeding roller, and outputs the original image. After reading the document, the sheet original is discharged and stacked on the sheet member mounting table.

Further, in recent years, with the spread of personal computers, networking of offices has been progressing, and printers are mainly used, so that demands for space saving and cost reduction have increased, and facsimile has been increasing. Multifunction printers having both functions and copy functions have been provided.

The sheet conveying device attached to such a multi-function image forming apparatus generally has a mounting table on which the original is mounted and a discharge table for reloading the discharged original. The device is supported via a hinge mechanism that can be opened and closed upward with respect to one end. As a result, when an opening / closing cover for maintenance is provided on the upper surface of the image forming apparatus main body, when a bound sheet member such as a book original is copied, or when the conveyed original has a paper jam. Then, the automatic document feeder can be positioned at the open position to perform a predetermined operation.

[0005] With the multi-functioning of the image forming apparatus as described above, a space-saving and easy-to-operate one has been demanded. There is provided a configuration in which a sheet member transport mechanism and a sheet stacking table are provided separately from each other in order to reduce opening and closing of the stacking table in parallel with the sheet mounting table of the sheet member conveying apparatus.

[0006]

However, according to the image forming apparatus having the above-described structure, the sheet conveying device is located at the open position while the sheets are stacked on the mounting table or the discharge table. In such a case, there is a problem that the sheet member slides down from the mounting table and falls to the rear side of the image forming apparatus, that is, the back side when viewed from the operation direction.

Therefore, it is necessary to check in advance whether a sheet is placed on the placing table or the discharge table, and if the sheet is placed, it is necessary to remove one end before opening the sheet conveying device. , Very poor operability. In addition, when a plurality of users use the documents, the originals are mixed due to the momentum dropped from the mounting table, and there is a disadvantage that the documents must be separated.

In order to solve the above-mentioned problems, a conventional sheet member conveying apparatus is disclosed in, for example, Japanese Patent Laid-Open No. 5-1168.
When the opening operation of the upper half of the image forming apparatus main body is detected as disclosed in Japanese Patent Application Laid-Open No. 04-2004, the document pressing means also serving as a document sending means presses against the upper portion of the document to prevent the document from dropping. Such a mechanism has been proposed.

However, in the above configuration, a press-contact / separation mechanism for the document pressing means is separately required, and a detection means for detecting the opening of the main body is also required. Therefore, the number of components is increased and the mechanism is complicated. The disadvantage is that it costs money.

[0010] In addition, in the case where the sheet document placing table and the discharge table are provided integrally, in a conventional sheet member transporting device that rotates the entire sheet member transporting device, it is heavy when opened and closed. As a result, there is also a problem that a considerable load is imposed on the user.

In order to solve the above-mentioned problems, according to the invention described in claim 1 of the present application, a mounting table on which a sheet member is mounted, and a connecting table connected to the mounting table. The image forming apparatus includes a conveying unit that conveys the sheet member, and a rotation mechanism that can rotate the mounting table from a horizontal position to an open position with the connection side of the conveyance unit as a rotation reference. It is provided in the provided sheet member conveying device, is stored in a non-operating position when the mounting table is in the horizontal position, and when the mounting table is opened, it is attached to one end of the sheet-shaped member mounted with the opening operation. A fall prevention mechanism is provided which is in contact with and is located at an operating position for preventing the sheet-like member from falling from the mounting table.

According to the first aspect of the present invention, when the mounting table on which the sheet-like member is mounted is opened to the open position by the rotating mechanism, the table automatically acts on the sheet member on the mounting table. Since the fall prevention mechanism for preventing the fall is provided, there is no need to remove the sheet member when the user releases the sheet member one by one, and there is no possibility that the sheet member is accidentally dropped due to forgetting.

According to the invention described in claim 2 of the present application, the rotating member is provided at the connection end of the mounting table with the transfer means and is in contact with the contact member provided on the upper surface of the image forming apparatus main body. A moving member, an urging means for applying an urging force to the rotatable member in a direction opposite to the turning direction, and a drop preventing means rotatable between an operating position and a non-operating position with the turning of the rotatable member. And a support shaft for coaxially supporting the pivoted member and the fall prevention means.

According to the present invention, the contact member is provided in the image forming apparatus main body, and the rotatable member which rotates in contact with the contact member is provided on the mounting table side. The mechanism is rotated, so that the sheet member can be prevented from falling.

According to the third aspect of the present invention, the contact member provided on the upper portion of the image forming apparatus main body is provided at a position other than the image reading means provided on the upper portion of the image forming apparatus main body. A contact member having a contact portion that comes into contact with a rotated member provided on the mounting table in accordance with the closing operation of the mounting table, and an inclined portion that urges the rotating member to rotate. Is provided.

According to the third aspect of the invention, the turning operation of the turning mechanism can be smoothly performed with the opening / closing operation of the opening / closing mechanism without obstructing the original reading operation by the image reading means. Therefore, it is possible to more reliably prevent the sheet-shaped member from falling by the fall prevention mechanism.

According to the invention described in claim 4 of the present application, at the end on the connection side of the transfer means with the mounting table, the pivoting operation of the drop prevention means to the non-operating position is allowed. When the is located at the closed position, a fall prevention mechanism having a storage portion for storing the fall prevention means is provided.

According to the present invention, when the opening / closing mechanism, which does not require the fall prevention mechanism, is closed, the fall prevention mechanism is housed in the transfer means, so that the fall prevention mechanism is located between the mounting table and the transfer means. There is no need to provide a gap that allows the rotation operation, and the fall prevention mechanism can be securely accommodated. Therefore, it is possible to provide a compact sheet member conveyance device without affecting the conveyance of the sheet member at all. .

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. First, FIG. 1 is an overall perspective view of an image forming apparatus as a multifunction machine having both a copying function and a facsimile function to which a sheet member conveying apparatus according to an embodiment of the present invention is applied, and FIG. It is. In FIGS. 1 and 2, the image forming apparatus 1 includes a main body 1a and a sheet member conveying device 1b disposed above the main body 1a.

The main body 1a comprises an image reading means 2, an optical unit 3, an image forming section 4 having a photosensitive drum 41, and a transfer paper transport mechanism 5. An operation panel 6 is provided at a position on the near side (FIG. 2) of the upper outer surface of the main body 1a. Further, a transfer paper discharge section 7 is formed at a position from the upper portion of the main body 1a to an intermediate portion in the depth direction of the main body 1a. A telephone 8 connected to a telephone line for transmitting / receiving an image of a sheet document to / from an external facsimile is attached to a side portion of the main body 1a. Since the image forming apparatus 1 normally performs a copying operation of a document and a facsimile transmission operation on the side of the main body 1a where the operation panel 6 is disposed, the side on which the operation panel 6 is disposed may be used. The side opposite to the side on which the operation panel 6 is provided is referred to as the front side, and the rear side is referred to as the rear side.

The image reading section 1b includes a first contact glass 11 mounted on the top of the main body 1a, and a second contact glass mounted on the top of the main body 1a and behind the first contact glass 11. 12, a sheet mounting table 13 which is disposed above the first contact glass 11 and covers the surface of the first contact glass 11 so as to be able to open and close, to which the fall prevention mechanism of the present invention is applied, and a second contact glass 12 , A sheet member transport mechanism 14 disposed above.

The first contact glass 11 constitutes a stationary sheet document reading area for reading an image of the sheet document by scanning a stationary sheet document with a scanner 22 described later constituting the image reading means 2. . Further, the second contact glass 12 forms a transport sheet document reading area for reading the image of the sheet document by moving the sheet document with respect to the stationary scanner 22. Next, the mounting table 13 of the sheet member has a concave portion formed on the upper surface side, and constitutes a sheet member discharging section 17 for receiving the sheet member discharged from the sheet member conveying mechanism 14. Further, when the sheet member is placed on the first contact glass 11, the presence of the sheet member is detected by the sheet member detection sensor S1, and a detection signal is output.

The sheet member transport mechanism 14 has a sheet member insertion opening 141 that opens to the front side, and also opens to the front side and is located below the sheet member insertion opening 141.
After the sheet member inserted into the sheet member discharge port 142 located above the sheet member discharge section 17 and the sheet member insertion port 141 is taken in toward the rear side, the conveyance direction is reversed at the intermediate position, and the front side is set. Sheet member outlet 14
2 is provided. The sheet member insertion portion 141 is provided with the sheet member
44 is integrally attached to a pair of support members 131 protruding at a position facing the rear side of the sheet member mounting table 13 (in the depth direction of the paper surface), and is disposed so as to be positioned above the sheet member mounting table 13. I have. The sheet member conveying section 143 includes a forward feed roller 143a from the upstream side to the downstream side,
A paper feed roller 143b, a first transport roller pair 143c, a second transport roller pair 143d, and a discharge roller pair (third transport roller pair) 143e are arranged in this order.
It is arranged in a state of being biased to the 3b side.

The first transport roller pair 143c, the second transport roller pair 143d, and the discharge roller pair 143e each include a drive roller and a driven roller. The forward feed roller 143a, the paper feed roller 143b, the drive roller of the first transport roller pair 143c, the drive roller of the second transport roller pair, and the drive roller of the discharge roller pair 143e are
The rotation of the drive motor M1 causes the sheet members to rotate in the directions of the arrows that convey the sheet members toward the downstream side, respectively. Further, the separating roller 143f includes a torque limiter. When only one sheet member passes between the sheet feeding roller 143b and the separating roller pair 143f, the torque applied to the separating roller 143f is large. When a plurality of sheet members passing between the sheet feeding roller 143b and the separation roller pair 143f are overlapped with each other, the torque applied to the separation roller 143f is small, so that the torque limiter acts to make the rotation impossible. . As a result, since the frictional force between the sheet members is smaller than the frictional force between the sheet members and the separating roller 143f, only the uppermost sheet member is conveyed downstream by the sheet feeding roller 143b.

The sheet member conveying section 143 includes a position near the upstream side of the sheet feeding roller 143b and the second conveying roller pair 143.
d and the sheet member detection sensors S2 and S
When the sheet member in a state of being stacked with the image forming surface facing upward is placed on the placement portion 144 of the sheet member and pushed to a position near the upstream side of the sheet feeding roller 143b, The sheet member detection sensor S2 detects the presence of the sheet member, and the drive motor M1 is driven according to an instruction signal given thereafter, and the sheet members are conveyed one by one downstream. When the leading end position of the conveyed sheet member reaches a position near the downstream side of the second pair of conveying rollers 143d, the sheet member detecting sensor S3 detects this, and the leading end position of the sheet member is set to the second contact glass 12. , The reading of an image by the scanner 22 described later is started. Thereafter, when the rear end position of the sheet member has passed through the second contact glass 12, the scanner 2
2 ends the image reading. The sheet member from which the image has been read is conveyed to the sheet member discharge port 142 by the discharge roller pair 143e. Sheet member mounting section 1
The sheet member placed on 44 is a sheet member detection sensor S
While 2 is ON, it is sequentially transported to the downstream side.

It should be noted that the sheet member is the second conveying roller pair 1
When the sheet passes through 43d, the upper and lower surfaces are inverted, and when the sheet reaches the position of the second contact glass 12, the image forming surface faces the second contact glass 12 so that an image can be read and the sheet member is discharged. The sheet members conveyed to the outlet 142 are discharged to the sheet member discharge unit 47, and are sequentially stacked upward with the image forming surface facing down. As a result, when the sheet members are collected from the sheet member discharge unit 17, the sheet members are stacked in the same order as the original.

As shown in FIG. 3, the mounting table 13 for the sheet member has a pair of arms 132 formed to extend rearward at opposing positions on the rear side (in the depth direction of the paper). Shaft 145a formed on 145
And is rotatably supported on the mounting table 13 for the sheet member.
When the lifting force is applied to the front side of the sheet glass, it is lifted up together with the sheet member mounting portion 144 with the shaft 145a as a fulcrum as shown by a dashed line, and the first contact glass 11 surface is opened. It is in a state where it is in a state where it is not.
When the force in the direction of lifting upward is released, the shaft 1
It descends by its own weight with 45a as a fulcrum, and is in a state of covering the first contact glass 11 surface.

Referring back to FIGS. 1 and 2, the image reading means 2 includes a guide rail 21 disposed along the side of the first and second contact glasses 11 and 12, and a guide rail 21.
And a scanner 22 serving as image reading means arranged so as to be able to reciprocate between the front side and the rear side along the line. The scanner 22 irradiates the image surface of the sheet member with the LE.
D and the like, an image reading unit 222 such as a CCD, and a mirror 223 for guiding a sheet document image to the image reading unit 222. Usually, the first contact glass 11 and the second contact glass 12 are provided. And stand by at the home position, which is an intermediate position between them.

When the sheet member is placed on the first contact glass 11, the scanner 22 detects the presence of the sheet member by the sheet member detection sensor S1, and responds to an instruction signal given thereafter to drive the drive motor M2. Is driven to temporarily operate the operation panel 6 from the home position.
It moves to the tip position of the side sheet member. Thereafter, the light source 221 is turned on to move from the near side, which is the leading end position of the sheet member, to the rear side, and the image surface of the sheet member is operated to read the image line by line. This read image data is subjected to predetermined data processing,
It is converted to a digital signal and stored in a memory (not shown).
When the reading of the sheet document image is completed, the scanner 22 turns off the light source 221 and returns to the home position.

When the sheet member is placed on the sheet member placement portion 144, the scanner 22 detects the presence of the sheet member by the sheet member detection sensor S2, and drives the drive motor in response to an instruction signal given thereafter. When M2 is driven, the second contact glass 12 is moved from the home position to the position of the second contact glass 12, and when the sheet member is conveyed by the sheet member conveying unit 14 and passes over the second contact glass 12, the second contact glass is moved to the second position. The image of the sheet member is read line by line in a state of resting on the position of the contact glass 12. The read image data is stored in a memory (not shown) in the same manner as described above. The light source 2
Reference numeral 21 is turned on before reading the image of the sheet member, and turned off after reading. Further, the scanner 22 returns to the home position when the conveyance of all the sheet members placed on the sheet member placement section 144 is completed.
Thus, at the position of the second contact glass 12,
Since the scanner 22 reads the image of the sheet member conveyed in a stationary state, the moving time of the scanner 22 as in the first contact glass 11 can be reduced, and the reading amount of the image per unit time can be increased. Become.

The optical unit 3 is disposed below the transfer paper discharge unit 7 and is an image of the sheet member read by the scanner 22 read from the memory not shown or from the memory not shown. A light emitting unit 31 for exposing the read image transmitted from an external facsimile onto the photosensitive drum 41, converting a bias signal generated based on the image data into a laser beam and outputting the laser beam, and a light emitting unit 31 A reflection mirror 32 is provided for reflecting the laser light from the section 31 toward the photosensitive drum 41. In the optical unit 3, each component is mounted in a housing 33 and integrally formed.
The main body 1a is disposed in the main body 1a while being fixed to the main body frame therein by means such as screws.

The image forming section 4 includes a charger 42 at an upper portion along the peripheral surface of the photosensitive drum 41, a developing section 43 at a front side of the charger 42, and a cleaning section 44 at a rear side of the charger 42. . The photoconductor drum 41 is rotated in the direction of the arrow by the rotation of the drive motor M3, and a charged area is formed on the peripheral surface at a position facing the charger 42. An electrostatic latent image is formed in this electrostatic area by laser light output from the optical unit 3, and the electrostatic latent image is developed into a toner image at a position facing the developing unit 43. A transfer roller 45 is disposed below the photoconductor drum 41. The photoconductor drum 41 on which the toner image is formed transfers the toner image to a transfer sheet at a position facing the transfer roller 45, and further rotates. The toner remaining on the peripheral surface at a position facing the cleaning unit 44 disposed on the downstream side in the direction is removed.

The image forming section 4 includes a housing 4
The housing 46 is removably mounted on a main body frame (not shown) in the main body 1a. A cover 48 that can be opened and closed on the front side with the shaft 481 at the lower end serving as a fulcrum is attached to the front side of the image forming section 4 of the main body 1a.
Can be taken out of the cover 48 to the outside of the main body 1a.

The transfer paper transport mechanism 5 is formed at a lower portion of the main body 1a, and is provided with a paper feed cassette loading section 52 for loading a paper feed cassette 51 in which transfer papers P are stacked and stored, and this paper feed cassette loading section. Paper cassette 51 loaded in 52
Paper feed unit 53 having paper feed rollers 531 for feeding the transfer paper P from the front side, and transfer paper drawn from the paper feed cassette 51 to the transfer paper discharge unit 7 via the photosensitive drum 41. A conveyance path 54, a pair of registration rollers 55 disposed along the transfer paper conveyance path 54, a fixing unit 56,
A pair of transport rollers 57 and a pair of discharge rollers 58 are provided.

The lower side of the paper feed cassette 51 serves as a rotation fulcrum, and the transfer paper pulled out by a paper feed roller 531 and a transfer paper mounting table 512 whose front side is urged upward by a spring 511. Guide 5 leading to transfer paper transport path 54
13 is provided inside, and is slid from the front side of the main body 1a to the sheet cassette loading section 52 to be mounted. The paper feed cassette 51 can be pulled out of the main body 1a by pulling it toward the front when replenishing transfer paper or when a jam occurs near the paper feed roller 531. The guide 513 is used to guide the transfer paper to the transfer paper transport path 54 above.
The second side has a concave shape, and a plurality of ribs 513a are provided at predetermined intervals along the transport direction on the contact surface side with the transfer paper, so that the transfer paper can be smoothly transported. Have been.

The paper supply section 53 has a separation means such as a separation claw or a separation roller (not shown) for preventing double feeding of transfer sheets, in addition to the sheet supply roller 531. The paper feed roller 531 is disposed above the paper feed cassette 52 and at a position closer to the front, and is rotated in the direction of the arrow by the rotational drive of the drive motor M3 via a clutch (not shown).
The sheet member is fed.

The transfer paper transport path 54 is a first pre-transfer guide for inverting the transfer paper drawn out to the front side of the paper supply cassette 51 to the rear side and feeding it between the photosensitive drum 41 and the transfer roller 45. 541 and a second pre-transfer guide 542, a post-transfer guide 543 for feeding the transfer paper on which the image has been transferred by the photosensitive drum 41 to the rear fixing unit 56, and the fixing unit 5
The first reversing guide 544 and the second reversing guide 544 for reversing the transfer paper passing through the transfer paper 6 in the transport direction and discharging the transfer paper to the transfer paper discharge unit 7 on the near side.
A reversing guide 545 is provided. Guides 541, 54
2, 543, 544, and 545 are formed of resin or the like, and a plurality of ribs are arranged at predetermined intervals along a conveyance direction on a contact surface side with the transfer paper so that the transfer paper can be smoothly conveyed. Has become.

The registration roller pair 55 is disposed between the first pre-transfer guide 541 and the second pre-transfer guide 542,
The drive is driven by the rotation of a drive motor M3 via an unillustrated clutch. The transfer paper is fed between the photosensitive drum 41 and the transfer roller 45 in synchronization with the formation of the electrostatic latent image on the photosensitive drum 41 by the optical unit 3. When the transfer of one transfer sheet is completed, the clutch is released and the driving is stopped. A transfer paper sensor S4 is provided immediately before the pair of registration rollers 55. When the leading end of the transfer paper is detected, the driving of the paper feed roller 531 is stopped after a predetermined time.

The fixing section 56 comprises a heat roller 561 located above and a pressure roller 562 located below, and is disposed between the post-transfer guide 543 and the first reversing guide 544. . The heat roller 561 has a heater inside, and a pressure roller 56 is provided on the heat roller 561 side.
2 are pressed by a predetermined spring pressure. Then, while fixing the toner image on the transfer paper conveyed between both rollers,
The transfer paper on which the toner image is fixed is conveyed to the first reversing guide 544 side. The transport roller pair 57 is disposed between the first reversing guide 544 and the second reversing guide 545,
The discharge roller pair 58 is located at the end position of the second reversing guide 545. A transfer paper sensor S5 is provided at a substantially intermediate position in the transport direction of the second reversing guide 545 so as to detect transfer paper transport abnormality.

The operation panel 6 includes a start switch 61,
A mode selection key 62 for selecting a copy mode and a facsimile transmission mode, an enlargement / reduction key 63, a numeric keypad 64, and other function keys 65 provided so that the user can arbitrarily set various functions are provided. The display section 66 is provided so that the function set by the user can be visually recognized.

The operation of the image forming apparatus configured as described above will be described below. First, the operation panel 6
When the copy mode or the facsimile transmission mode is selected by the mode selection key 62, and the sheet member is placed on the sheet member placement portion 144, the sheet member detection sensor detects that and turns on the start switch 61 of the operation panel 6. Thus, the sheet member is conveyed onto the second contact glass 12 by the sheet member conveying section 14. At this time, the scanner 22 that has moved from the home position to the position of the second contact glass 12 reads an image of the sheet member, and stores the read image of the sheet member in a memory (not shown). The sheet member for which the image reading has been completed is discharged to the sheet member discharge unit 17. When the sheet member to be copied or transmitted by facsimile is a bound sheet member such as a book, the sheet member is directly placed on the first contact glass 11. Then, when the sheet member detection sensor S1 detects this and turns on the start switch 61, the scanner 22 scans the image surface of the sheet member to read the image, and stores the read image in a memory (not shown). Further, when an image is transmitted from an external facsimile via a telephone line, the signal is detected, the reception mode is automatically set, and the received image data (not shown) is stored in the memory.

In the facsimile transmission mode, image data stored in a memory (not shown) is read out and transmitted to a destination facsimile through a telephone line. In the copy mode or the facsimile reception mode, the image stored in the memory (not shown) is transferred to a transfer sheet and discharged to the transfer sheet discharge unit 7.

That is, in the copying mode or the facsimile receiving mode, the photosensitive drum 41 is charged by the charger 42, and a laser beam corresponding to the image data stored in the memory (not shown) is emitted, so that the photosensitive drum 41 is discharged. The exposure forms an electrostatic latent image. Next, the developing unit 4
The toner supplied from 3 to the photosensitive drum 41 adheres to the electrostatic latent image to form a toner image.

On the other hand, the transfer paper stored in the paper feed cassette 51 is fed by a paper feed roller 531 to a first pre-transfer guide 541.
Is fed to the registration roller pair 55 side through
In synchronization with the formation of the electrostatic latent image, the photosensitive drum 41 is moved by the registration roller pair 55 via the second pre-transfer guide 542.
And the transfer roller 45. The transfer paper conveyed to the gap between the photosensitive drum 41 and the transfer roller 45 is
After the toner image on the photosensitive drum 41 is transferred by the transfer roller 45 to which a voltage having a polarity opposite to the polarity of the electrostatic latent image is applied, the toner image is separated from the photosensitive drum 41, and the post-transfer guide 5
The toner image is conveyed to the fixing unit 56 via the fixing unit 43 and is fixed thereto. Further, the transfer paper on which the toner image is fixed is discharged to the transfer paper discharge unit 7 by the pair of conveying rollers 57 and the pair of discharge rollers 58 via the first reversing guide 544 and the second reversing guide 545.

Next, an example of the specific structure of the fall prevention mechanism according to the present invention will be described. 4 and 5 show a specific example of the fall prevention mechanism according to the present invention. FIG. 3 is an overall view of the fall prevention mechanism, and FIGS. 4A to 4E show a fall due to the opening operation of the sheet conveying device. 4 shows the movement of the prevention mechanism over time.

The rotating shaft 133 shown in FIG. 3 is rotatably supported at the position in FIG. 3 so as to penetrate the sheet member mounting table 13. Abutted members 135 urged in the direction of arrow A by springs 134 are fixed to both ends of the rotating shaft 133. The contact member 135 contacts at least one contact member 136 provided on a frame portion on the upper surface of the image forming apparatus main body shown in FIGS. 3 and 5. As shown in FIG. 4, the lowermost part of the contacted member that comes into contact with the contact portion is formed in a gentle arc shape, and is used when the sheet member transport device 1b is rotated from the horizontal position to the upper open position. FIG. 4a sequentially turns from the state of FIG. 4a to FIG. 4e.

More specifically, the contact member 136 includes a flat portion whose upper surface is parallel to the upper surface of the main body of the image forming apparatus, and an inclined portion which is gently inclined downward. The sheet member conveying device is closed on the upper surface of the apparatus main body 1a, and the contact member 136, the contacted portion 135 of the drop prevention mechanism, and the drop prevention member 137 are in a positional relationship as shown in FIG. 4E. At this time, the fall prevention member 137 is in the concave storage portion 201 provided on the sheet mounting table so as not to hinder the conveyance of the sheet members stacked on the sheet member mounting table 13, and
It is preferable that it is configured to be accommodated in a sheet member transporting section 14 (FIGS. 3 and 5) provided at an end on the connection side with the sheet mounting table. At the horizontal position where the sheet member is conveyed, the fall prevention member 137 is hidden by the lower roller 14X. Then, the paper is fed by 14Z and 14X. When the sheet mounting table 13 starts to rotate upward, the contact portion 13 is gradually moved by the urging force of the spring 134.
5 is smoothly rotated in the direction of arrow B shown in FIG. 5 in a state of contacting the inclined portion on the upper surface of the contact member 136. By the rotation of the contacted portion 135, the rotation shaft 133 rotatably supported by the sheet mounting table 13 also rotates in the arrow B direction. The rotation of the rotation shaft 133 also causes the fall prevention member 137 fixed coaxially to rotate in the arrow B direction.

Then, the fall prevention member 137 is rotated from the storage portion to an operation position where it acts on the sheet member, and is protruded. As shown in FIG. 3, the fall prevention member 137 contacts the lower end side of the sheet when the sheet mounting table is located at the open position, that is, the upstream end in the conveyance direction, and the sheet member is moved from the sheet mounting table Is provided. When the sheet mounting table is located at the open position, the bent portion can prevent the sheet from dropping from the end of the sheet mounting table 13.

Then, when the sheet mounting table is again placed in the closed state, which is the horizontal position from the open position, the turning operation proceeds sequentially from FIG. 4A to FIG. Become. That is, the lower part of the abutted member 135 abuts on the upper surface of the abutting member 136 on the apparatus main body side, and the turning operation is started in opposition to the urging force of the spring 134. As described above, the contact member 136 on the apparatus main body side is provided with a gently inclined portion on the upper surface thereof, so that the arc portion provided at the lower portion of the contacted member smoothly rotates along the inclined surface. Will be done. Then, with the rotation of the contacted member 135, the rotation shaft 133 to which the contacted member is fixed is also rotated. Then, at the time of opening, the fall prevention member 137 which has been positioned by the urging force of the spring 134 at the operation position protruding from the mounting surface on the sheet mounting table is rotated, and is stored in the above-described storage portion which does not act on the sheet member. It is.

The contact member in this embodiment has a shape including a flat portion and an inclined portion, but is not particularly limited to this. The shape may be a gentle arc or a semicircle, as long as the rotation of the contacted member is performed smoothly and appropriately. Further, the contact member may also serve as a position regulating member for maintaining a gap for appropriately conveying the sheet member between the upper surface of the image forming apparatus main body 1a and the sheet conveying device 1b. Also, the sheet mounting table 13
A rotation shaft provided with a fall prevention member is also provided on the sheet mounting portion 144 side so as to be linked to the rotation operation of the drop prevention mechanism on the side, and the sheet member before image reading is performed with the rotation operation of the sheet mounting table. May be configured to prevent falling.

Further, in the present invention, the transfer paper discharge section 7 for discharging the transfer is provided in the image forming apparatus main body as an embodiment, but the transfer paper transport path which can be transported toward the upper part of the apparatus. If the sheet conveyance device is not currently used and the sheet detection sensor detects that no sheet is loaded on both the sheet placing table 13 and the sheet placing section 144, the sheet placing table is provided. Even if it is configured so that the user can arbitrarily discharge the transfer paper 13 onto the sheet mounting portion 144 or the sheet mounting portion 144, the transfer paper can be easily taken out and the state of the transfer paper can be easily checked, which is convenient.

[0051]

As described above, according to the invention as claimed in the present application, a fall prevention mechanism capable of reliably preventing a member from falling with a simpler structure is provided. Workability is improved, and a highly reliable device can be provided at low cost.

In addition, since an opening and closing mechanism that can open and close only the sheet mounting table is provided, the burden on the user during opening and closing can be reduced, and the life of the opening and closing mechanism itself can be extended.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an image forming apparatus having a fall prevention mechanism according to an embodiment of the present invention and a sheet conveying device to which the mechanism is applied.

FIG. 2 is an internal configuration diagram of an image forming apparatus having the sheet conveying device shown in FIG.

FIG. 3 is a side view showing an opening / closing operation of a sheet mounting table in the sheet conveying apparatus shown in FIG.

FIG. 4 is an operation diagram of a fall prevention member according to the present invention.

FIG. 5 is a perspective view of a main part showing a configuration of a fall prevention mechanism according to the present invention.

FIG. 6 is a side view for illustrating a rotation operation of the fall prevention mechanism according to the present invention.

FIG. 7 illustrates an image forming apparatus provided with a sheet conveying device according to the related art of the present invention.

[Explanation of symbols]

 1a: Image Forming Apparatus Main Body 1b: Sheet Conveying Device 13: Sheet Member Placing Unit 14: Sheet Member Conveying Unit 144: Sheet Part Placing Unit 14X: Lower Feed Roller 14Z: Upper Feed Roller 17: Sheet Member Discharge Unit 131 : Support member 133: Rotating shaft 134: Spring 135: Contact member 136: Contact member 137: Fall prevention member 200: Document 201: Concave storage section

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[Procedure amendment]

[Submission date] March 21, 2000 (200.3.2
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention A sheet conveying device and Bei this
Image forming apparatus

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device, and more particularly, to a sheet conveying device such as an automatic document conveying device installed above an image forming apparatus. More specifically, in a device in which a mounting table for mounting a sheet member such as a document is formed to be openable and closable, when the mounting table is opened,
The present invention relates to a fall prevention mechanism for preventing a document or the like from falling from a mounting table.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a facsimile or a copying machine has been provided in which an automatic document feeder (sheet member feeder) is disposed above an image forming apparatus main body. FIG. 7 shows an example of this type of image forming apparatus. The apparatus shown in FIG. 7 is provided with an automatic document feeder (hereinafter, referred to as an ADF device) at an upper portion of a main body 600.
The ADF device includes a document table 610 and a transport mechanism 620 provided on the right side of the table 610 in the drawing.
In addition, the main body 600 includes a scanner 630 disposed below the mounting table 610, an optical unit 640 disposed below the scanner 630, and an image forming unit 650 disposed below the optical unit 640. I have. Image forming unit 65
0 has a photosensitive drum 651 and a photosensitive drum 6
Reference numeral 51 denotes an image of a document exposed by a laser beam output from the optical unit 640, which is visualized as a toner image and transferred to a transfer sheet. The main body 600 further includes a transfer sheet feeding unit 660 having a sheet cassette 661 disposed below the image forming unit 650, a fixing unit 670 disposed downstream of the transfer sheet feeding unit 660, and a fixing unit 670. And a transfer paper discharge section 680 arranged on the downstream side.

[0003] The transport mechanism 620 of the ADF apparatus includes a mounting table 6.
The originals stacked on the sheet 10 are conveyed one by one to an image reading section of the image forming apparatus main body by sheet feeding means such as a sheet feeding roller, and the originals are returned to the mounting table 10 after reading of the original image is completed. is there. In recent years, with the spread of personal computers, networking of offices has progressed,
The mainstream is to use printers in offices. Demand for space saving in offices and cost reduction of equipment used in offices has increased,
As a result, a multifunction (multifunctional) printer (image forming apparatus) having both a facsimile function and a copy function has been provided. An ADF device attached to such a multi-function image forming apparatus generally includes a document mounting table and a discharge table for reloading a document discharged from the image reading unit. The mounting table and the discharge table are mounted via a hinge mechanism such that one end side thereof can be freely opened and closed upward with respect to the image forming apparatus main body. Thus, in a case where a thick original such as a book original which is stapled is copied, or when a conveyed original has a paper jam, the operation is performed with the ADF device located at the open position. be able to.

[0004] With the multifunctionalization of the image forming apparatus as described above, there is a demand for a further space-saving one with good operability. Therefore, a transfer table for the transfer paper after image formation is provided in parallel with the mounting table of the ADF device facing the front side of the main body, and in order to reduce the operation force for opening and closing the ADF device, the mounting table and the discharge table There is also provided an apparatus in which a portion provided and a portion provided with a transport mechanism are separated from each other so that only a portion provided with a mounting table and a discharge table can be opened and closed.

[0005]

However, in the conventional apparatus as described above, when the ADF device is opened while the originals are stacked on the mounting table or the discharge table, the originals are read from the mounting table or the discharge table. Slides down and falls on the back side of the image forming apparatus, that is, on the back side when viewed from the operation direction. When opening the ADF device to prevent the document from falling as described above, it is necessary to check in advance whether the document is placed on the loading table or the output tray. If so, they must be removed once and the ADF device must be opened. Therefore, the operability is poor. When a plurality of originals drop, it is troublesome to sort the originals after picking them up. In order to solve the above problems,
For example, a technique disclosed in Japanese Patent Application Laid-Open No. 5-116804 has been proposed. Here, when the opening operation of the upper half of the image forming apparatus main body is detected, the original pressing means, which is also the original sending means, is pressed against the upper part of the original to prevent the original from dropping. However, in the above-described configuration, a press-contact / separation mechanism for the document pressing means is separately required, and a detection means for detecting opening of the main body is also required. Therefore, the number of parts increases, the mechanism becomes complicated, and cost increases. Would. Further, in the case where the document mounting table and the discharge table are provided integrally as described above, there is also a problem that the weight of the entire ADF apparatus becomes heavy, and a load is imposed on an operator during opening and closing operations. .

[0006]

A sheet member conveying device according to the present invention is provided on an upper portion of an image forming apparatus main body, and conveys a sheet member. The sheet member conveying device includes a mounting table, a conveying mechanism,
And a fall prevention mechanism. The mounting table is provided to be openable and closable with respect to the image forming apparatus main body, and mounts a sheet member. The transport mechanism transports the sheet member placed on the mounting table. The fall prevention mechanism retreats so as not to hinder the conveyance of the sheet member when the mounting table is closed, and when the mounting table is open, the sheet member falls from the mounting table with the opening operation of the mounting table. To prevent According to this device, since the sheet member on the mounting table is prevented from dropping with the opening operation of the mounting table, the user does not need to remove the sheet member when the mounting table is opened. In this sheet member conveying device, it is preferable that the mounting table can be opened and closed independently of the conveying mechanism. In this sheet member conveyance device, it is preferable that the fall prevention mechanism includes a rotation shaft, a fall prevention member, a biasing member, and a regulating member. The rotating shaft is rotatably supported at the downstream end of the mounting table in the transport direction. The fall prevention member is rotatable with the rotation axis,
A first contactable end of the sheet member placed on the mounting table
A position and a second position that does not abut the end of the sheet member can be taken. The urging member urges the fall prevention member toward the first position. The regulating member positions the fall prevention member at the second position when the mounting table is closed. In this sheet member conveyance device, the fall prevention mechanism may further include a rotating member that can rotate together with the rotation shaft and the fall prevention member,
In this case, the urging member urges the rotation preventing member to urge the fall prevention member to the first position side, and the regulating member is provided on the upper surface of the image forming apparatus main body, and the mounting table is closed. In this state, the contact member is preferably an abutting member that abuts on the rotating member to position the drop prevention member at the second position. In this sheet member conveying device, when the image reading device is provided on the upper portion of the image forming apparatus main body, the contact member is provided at a position other than the image reading device,
It has a contact portion that contacts the rotating member when the mounting table is closed, and an inclined portion that contacts the rotating member as the mounting table opens and closes to smoothly rotate the rotating member. Preferably.

In this sheet member conveying apparatus, it is preferable that a storage portion for storing the drop prevention member at the second position is formed at the downstream end of the mounting table in the conveying direction. In this sheet member conveying apparatus, it is preferable that the conveying mechanism has a supply mechanism and a discharge mechanism. The supply mechanism supplies the sheet member mounted on the mounting table to a position corresponding to the image reading unit of the image forming apparatus main body. The discharge mechanism discharges the sheet member on which the image has been read by the image reading unit onto the mounting table. An image forming apparatus according to the present invention includes an image forming apparatus main body and a document conveying device. The image forming apparatus includes an image reading unit that reads an image of a document, a transfer paper conveyance mechanism that conveys transfer paper, and an image forming unit that forms an image read by the image reading unit on the conveyed transfer paper. Have. The document feeder is provided on an upper portion of the image forming apparatus main body, and includes a mounting table, a transfer mechanism, and a fall prevention mechanism. The mounting table is provided to be openable and closable with respect to the image forming apparatus main body, and mounts an original. The transport mechanism transports the original placed on the mounting table. The drop-prevention mechanism retracts the document so that it does not hinder the conveyance of the document when the document table is closed, and prevents the document from dropping from the document table when the document table is opened when the document table is opened. I do. In this image forming apparatus, it is preferable that the mounting table can be opened and closed independently of the transport mechanism. In this image forming apparatus, it is preferable that the fall prevention mechanism includes a rotation shaft, a fall prevention member, a biasing member, and a regulating member. The rotating shaft is rotatably supported at the downstream end of the mounting table in the transport direction. The fall prevention member is rotatable with the rotation shaft, and can have a first position capable of contacting an end of the document placed on the mounting table and a second position not contacting the end of the document. The urging member urges the fall prevention member toward the first position. The regulating member positions the fall prevention member at the second position when the mounting table is closed.

[0008]

An embodiment of the present invention will be described below with reference to the accompanying drawings. First, FIG. 1 is an overall perspective view of an image forming apparatus having an ADF device as a sheet member conveying device according to an embodiment of the present invention. The image forming device shown here has both a copying function and a facsimile function. It is a multifunction machine. FIG. 2 is a sectional view of the image forming apparatus shown in FIG. In these figures, the image forming apparatus 1 has a main body 1a and an ADF device 1b disposed on the upper part of the main body 1a. The main body 1 a includes an image forming unit 4 including an image reading unit 2, an optical unit 3 and a photosensitive drum 41, and a transfer paper transport mechanism 5. An operation panel 6 is provided on the front side (the right side in FIG. 2) of the upper outer surface of the main body 1a. In addition, a transfer paper discharge section 7 is formed in the upper part of the main body 1a from the near side to the middle part in the depth direction of the main body 1a. A telephone 8 for transmitting / receiving an image of a document to / from an external facsimile is attached to a side portion of the main body 1a. Since the image forming apparatus 1 normally performs a copying operation of a document and a facsimile transmission operation on the side of the main body 1a where the operation panel 6 is disposed, the side on which the operation panel 6 is disposed. Is referred to as a near side, and a side facing the side where the operation panel 6 is provided is referred to as a rear side. Further, a first contact glass 11 is provided on the top of the main body 1a, and a second contact glass 12 is provided on the top of the main body 1a and behind the first contact glass 11. The first contact glass 11 is arranged in the still original reading area. Here, the stationary document reading region is a region where the image of the document is read by scanning a stationary document with a scanner 22 described later that constitutes the image reading unit 2. When a document is placed on the first contact glass 11, the document is detected by the document detection sensor S1 and a detection signal is output. Further, the second contact glass 12 is arranged in the moving document reading area. The moving document reading region is a region where the image of the document is read by moving the document with respect to the stationary scanner 22.

The ADF apparatus 1b includes a document table 13 and
And a transport mechanism 14 for transporting the original. Mounting table 1
3 is disposed above the first contact glass 11,
The first contact glass 11 surface is openably and closably covered. The drop prevention mechanism of the present invention is applied to the mounting table 13. The transport mechanism 14 is provided above the second contact glass 12. The mounting table 13 has a concave portion formed on the upper surface side, and the concave portion serves as a discharge unit 17 that receives a document discharged from the transport mechanism 14. The transport mechanism 14 has a document insertion port 1 that opens to the front side.
41, a document discharge port 142, and a document transport unit 143. The document discharge port 142 is opened toward the apparatus in the same manner as the document insertion port 141, is positioned below the document insertion port 141, and is positioned above the discharge unit 17. The document transport unit 143 captures the document inserted into the document insertion port 141 toward the rear side, and then reverses the transport direction at an intermediate position and transports the document to the document output port 142 on the near side. A document placement section 144 is provided in front of the document insertion port 141. The document placement section 144
It is disposed above the mounting table 13, and is integrally attached to a pair of supports 131 that are provided to protrude upward at a position facing the rear side of the mounting table 13 (in the depth direction of the paper). The document feeder 143 includes a forward feed roller 143a and a paper feed roller 143 from the upstream side to the downstream side in the transport direction.
b, the first conveying roller pair 143c (the roller 143c ′,
Roller 143c ″), second conveying roller pair 143d
(A roller 143d 'and a roller 143d'') and a discharge roller pair (a third transport roller pair) 143e (the roller 143).
e 'and rollers 143e'') are sequentially killed. Further, the separating roller 143f is disposed in a state of being urged toward the sheet feeding roller 143b. First transport roller pair 14
3c, second transport roller pair 143d and discharge roller pair 1
Reference numeral 43e includes a driving roller and a driven roller. Forward feed roller 143a, paper feed roller 143b,
The drive roller of the first transport roller pair 143c, the drive roller of the second transport roller pair, and the drive roller of the discharge roller pair 143e rotate in the direction of transporting the document downstream by driving the drive motor M1. . The separating roller 143f has a torque limiter. When only one document passes between the sheet feeding roller 143b and the separating roller pair 143f, the torque applied to the separating roller 143f is large. When a plurality of originals passing between the paper feed roller 143b and the separation roller pair 143f are overlapped, the torque applied to the separation roller 143f is small, and the torque limiter acts to disable rotation. As a result, since the frictional force between the originals is smaller than the frictional force between the originals and the separating roller 143f, only the uppermost original is conveyed downstream by the paper feed roller 143b.

A document feeder 143 includes a paper feed roller 143.
Document detection sensors S2 and S3 are respectively disposed at a position near the upstream side of b and a position near the downstream side of the second conveying roller pair 143d. Thus, when the document stacked with the image forming surface facing upward is placed on the document placing portion 144 and pushed to a position near the upstream side of the paper feed roller 143b, the document detection sensor S2 detects the presence of the document. Then, the drive motor M1 is driven according to the instruction signal given thereafter, and the documents are conveyed one by one to the downstream side. When the leading end position of the conveyed document reaches a position near the downstream side of the second conveyance roller pair 143d, the document detection sensor S3 detects this, and
In accordance with this detection signal, control is performed such that when the leading end position of the document reaches the second contact glass 12, image reading by the scanner 22 described later is started.
Thereafter, the rear end position of the document is moved to the second contact glass 12.
Is controlled so that the reading of the image by the scanner 22 ends when the scanning has been completed. The document whose image has been read is conveyed to the document discharge port 142 by the discharge roller pair 143e. The original placed on the original placing section 144 is sequentially transported to the downstream side while the original detection sensor S2 is ON. The upper and lower surfaces are inverted when the document passes through the second pair of conveying rollers 143 d, and when the original reaches the position of the second contact glass 12, the image forming surface faces the second contact glass 12. Images can be read. Further, the document conveyed to the document discharge port 142 is discharged to the discharge unit 17 and is stacked on the top with the image forming surface downward. As a result, when the documents are collected from the discharge unit 17, the documents are stacked in the same order as the original. In addition, the mounting table 13
As shown in FIG. 3, a pair of arms 132 are formed extending rearward at opposing positions on the rear side (in the depth direction of the paper). On the other hand, as shown in FIGS. 1 and 2, an upstream guide 145 having a shaft 145a projecting in the lateral direction is formed on the main body 1a side. Is rotatably supported by the shaft body 145a. As a result, when the front side of the mounting table 13 is lifted, the mounting table 13 is lifted up together with the document mounting section 144 with the shaft body 145a as a fulcrum, as shown by the dashed line in FIG. The document placing surface of the glass 11 is opened. The mounting table 13
Is released, the mounting table 13 is lowered by its own weight with the shaft body 145a as a fulcrum, and the mounting table 13 covers the original mounting surface of the first contact glass 11.

As shown in FIG. 1 and FIG.
Are arranged along a side of the first and second contact glasses 11, 12, and are reciprocally movable between the near side and the rear side along the guide rail 21. And a scanner 22. The scanner 22 includes a light source 221 composed of an LED or the like that irradiates an image surface of a document, a reading unit 222 composed of a CCD or the like, and a mirror 223 that guides the document image to the reading unit 222. It is waiting at a home position which is an intermediate position between the glass 11 and the second contact glass 12. Here, when a document is placed on the first contact glass 11, the presence of the document is detected by the document detection sensor S1, and the drive motor M2 is driven according to an instruction signal given thereafter, whereby The scanner 22 once moves from the home position to the leading end position of the document on the operation panel 6 side. Then, the light source 221 is turned on, and the scanner 22 moves from the front side, which is the leading end position of the document, to the rear side, scans the image surface of the document, and reads the image line by line. This read image data is
After a predetermined data processing, it is converted into a digital signal and stored in a memory (not shown). When the reading of the document image is completed, the light source 221 is turned off, and the scanner 22 returns to the home position. When a document is placed on the document placement section 144, the document is detected by the document detection sensor S2, and the drive motor M2 is driven in response to an instruction signal given thereafter, whereby the scanner 22 is moved from the home position. It is moved to the position of the second contact glass 12. Then, when the document is transported by the transport mechanism 14 and passes over the second contact glass 12, the scanner 22 reads the document image line by line. The read image data is stored in a memory (not shown) in the same manner as described above. The light source 221 is turned on before reading an image on a document, and is turned off after reading. When all the originals placed on the original placing section 144 have been conveyed, the scanner 22 returns to the home position.
Thus, at the position of the second contact glass 12,
Since the scanner 22 reads the document image in a stationary state, the moving time of the scanner 22 as in the first contact glass 11 can be reduced, and the reading amount of the image per unit time can be increased.

The optical unit 3 is disposed below the transfer paper discharge unit 7, and the scanner 2 read from the memory.
The original image read in step 2 or the image read from the memory and transmitted from an external facsimile is exposed on the photosensitive drum 41. The optical unit 3 includes a light-emitting unit 31 that converts a weighted signal generated based on image data into a laser beam and outputs the laser beam;
And a reflection mirror 32 for reflecting the laser light from the first to the photosensitive drum 41. Each component of the optical unit 3 is attached to the housing 33 and is integrally formed with the housing 33. The housing 33 is fixed to a main body frame in the main body 1a by means of screws or the like. It is arranged in the main body 1a. The image forming unit 4 includes a charger 42 on the upper side, a developing unit 43 on the near side of the charger 42, and a charger 4 along the peripheral surface of the photosensitive drum 41.
The cleaning unit 44 is disposed behind the cleaning unit 2. The photoreceptor drum 41 is rotated in the direction of the arrow by the driving of the drive motor M3, and a charged area is formed on the peripheral surface at a position facing the charger 42. An electrostatic latent image is formed in this electrostatic area by laser light output from the optical unit 3, and the electrostatic latent image is developed into a toner image at a position facing the developing unit 43. A transfer roller 4 is provided below the photosensitive drum 41.
The toner image on the photosensitive drum 41 is transferred to a transfer sheet at a position facing the transfer roller 45.
Further, the toner remaining on the peripheral surface of the photosensitive drum 41 is removed at a position facing the cleaning unit 44 on the downstream side in the rotation direction. Each constituent member of the image forming section 4 is mounted in a housing 46 and is integrally formed with the housing 46. The housing 46 is detachably mounted on a main body frame (not shown) in the main body 1a. A cover 48 is provided on the front side of the image forming unit 4 of the main body 1a.
It can be opened and closed to the near side with 81 as a fulcrum. Thereby, the cover 48 is opened, and the image forming section 4 is connected to the main body 1a.
It can be taken out from the outside.

The transfer paper transport mechanism 5 is formed at the lower part of the main body 1a, and has a paper feed cassette loading section 52, a paper feed section 53, and a transfer paper transport path 54. The transfer paper transport mechanism 5 includes a registration roller pair 55, a fixing unit 56, a transport roller pair 57, and a discharge roller pair 58 disposed along the transfer paper transport path 54. Paper cassette loading unit 52
Is loaded with a paper feed cassette 51 in which transfer papers P are stacked and stored. The paper supply unit 53 includes a paper supply roller 531, and the transfer paper P in the paper supply cassette 51 loaded in the paper supply cassette loading unit 52 is sent out from the near side by the paper supply roller 531. The transfer paper transport path 54 is for guiding the transfer paper drawn from the paper supply cassette 51 to the transfer paper discharge unit 7 via the photosensitive drum 41. The paper feed cassette 51 transfers the transfer paper pulled out by the paper feed roller 531 and the transfer paper loading table 512 urged upward by a spring 511 to the transfer paper transport path 54 at the lower rear side and the front side urged upward by a spring 511. A guide 513 for guiding is provided inside. The paper feed cassette 51 is slid from the front side of the main body 1a to the paper feed cassette loading section 52 and mounted. The paper feed cassette 51 can be pulled out of the main body 1a by pulling it toward the front when replenishing the transfer paper or when a jam occurs near the paper feed roller 531. Note that the guide 513 is formed in a curved shape in which the transfer paper mounting table 512 side is concave in order to guide the transfer paper to the upper transfer paper transport path 54. Further, a plurality of ribs 513a are provided at predetermined intervals along the transport direction on the contact surface side of the guide 513 with the transfer paper, so that the transfer paper can be smoothly transported. The paper supply unit 53 has a separation means such as a separation claw or a separation roller (not shown) for preventing double transfer of the transfer sheet, in addition to the sheet supply roller 531. The paper feed roller 531 is
The drive motor M3 is disposed above the sheet cassette 52 and at a position nearer to the front, and via a clutch (not shown).
Is rotated in the direction of the arrow by the drive of
To transfer the transfer paper.

The transfer paper transport path 54 is a first pre-transfer guide for inverting the transfer paper drawn out to the front side of the paper supply cassette 51 to the rear side and feeding it between the photosensitive drum 41 and the transfer roller 45. 541 and a second pre-transfer guide 542, a post-transfer guide 543 for feeding the transfer paper on which the image has been transferred by the photosensitive drum 41 to the rear fixing unit 56, and the fixing unit 5
The first reversing guide 544 and the second reversing guide 544 for reversing the transfer paper passing through the transfer paper 6 in the transport direction and discharging the transfer paper to the transfer paper discharge unit 7 on the near side.
A reversing guide 545 is provided. Guides 541, 54
2, 543, 544, and 545 are formed of resin or the like, and a plurality of ribs are arranged at predetermined intervals along a transport direction on a contact surface side with the transfer paper, so that the transfer paper is smoothly transported. I can do it. Registration roller pair 55
Are the first pre-transfer guide 541 and the second pre-transfer guide 542
And is driven by the drive of the drive motor M3 via a clutch (not shown). The transfer paper is fed between the photosensitive drum 41 and the transfer roller 45 in synchronization with the formation of the electrostatic latent image on the photosensitive drum 41 by the optical unit 3. When the transfer of one transfer sheet is completed, the clutch is released and the driving is stopped.
Immediately before the registration roller pair 55, the transfer paper sensor S4
When the leading end of the transfer sheet is detected, the drive of the sheet feed roller 531 is stopped after a predetermined time. The fixing unit 56 includes a heat roller 561 located above and a pressure roller 562 located below, and is disposed between the post-transfer guide 543 and the first reversing guide 544. The heat roller 561 has a heater inside, and a pressure roller 562 is provided on the heat roller 561 side.
Are pressed by a predetermined spring pressure. Then, while the toner image is fixed on the transfer paper conveyed between both rollers, the transfer paper on which the toner image is fixed is conveyed to the first reversing guide 544 side. The transport roller pair 57 is provided with the first reversing guide 5.
The discharge roller pair 58 is disposed between the second reversing guide 545 and the discharge roller pair 58. A transfer paper sensor S5 is provided at a substantially intermediate position in the transport direction of the second reversing guide 545 so as to detect transfer paper transport abnormality.

The operation panel 6 includes a start switch 61,
A mode selection key 62 for selecting a copy mode and a facsimile transmission mode, an enlargement / reduction key 63, a numeric keypad 64, and other function keys 65 provided so that the user can arbitrarily set various functions are provided. The display section 66 is provided so that the function set by the user can be visually recognized. The operation of the image forming apparatus configured as described above will be described below. First, a copy mode or a facsimile transmission mode is selected by the mode selection key 62 of the operation panel 6 and when a document is placed on the document placing portion 144, that is detected by the document detection sensor.
When the start switch 61 of the operation panel 6 is turned on, the document is transported onto the second contact glass 12 by the transport mechanism 14. At this time, the image of the original is read by the scanner 22 moved from the home position to the position of the second contact glass 12, and the read original image is stored in the memory. The document whose image has been read is discharged to the discharge unit 17. When the original to be copied or transmitted by facsimile is bound like a book, the original is placed on the first contact glass 11.
Place directly on top. Then, the document is detected by the document detection sensor S1, and the start switch 61 is turned on, whereby the image surface of the document is scanned by the scanner 22 and the image is read. The read image is stored in the memory. When an image is transmitted from an external facsimile through a telephone line, the signal is detected, the mode is automatically set to the reception mode, and the received image data is stored in the memory. In the facsimile transmission mode, the image data stored in the memory is read and transmitted to the other party's facsimile through the telephone line. In copy mode or facsimile reception mode,
The image stored in the memory is transferred to a transfer sheet and discharged to a transfer sheet discharge unit 7.

That is, in the copy mode or the facsimile reception mode, the photosensitive drum 41 is charged by the charger 42, and a laser beam corresponding to the image data stored in the memory is emitted to expose the photosensitive drum 41. This forms an electrostatic latent image. Next, the toner supplied from the developing unit 43 to the photosensitive drum 41 adheres to the electrostatic latent image to form a toner image. On the other hand, the transfer paper stored in the paper feed cassette 51 is fed by the paper feed roller 531 to the pair of registration rollers 55 via the first pre-transfer guide 541. The transfer paper is transferred to the second pre-transfer guide 5 by the registration roller pair 55 in synchronization with the formation of the electrostatic latent image.
The sheet is conveyed to the gap between the photosensitive drum 41 and the transfer roller 45 through the transfer roller. Next, the photosensitive drum 41 is moved by the transfer roller 45 to which a voltage having a polarity opposite to the polarity of the electrostatic latent image is applied.
Is transferred to the transfer paper, and thereafter, the transfer paper is separated from the photosensitive drum 41 and conveyed to the fixing unit 56 via the post-transfer guide 543. The fixing section 56 fixes the toner image on the transfer paper. Further, the transfer paper on which the toner image is fixed is discharged to the transfer paper discharge unit 7 via the first reversing guide 544 and the second reversing guide 545 by the conveying roller pair 57 and the discharging roller pair 58. Next, an example of a specific configuration of the fall prevention mechanism will be described.
FIGS. 3, 4, and 5 show specific examples of the fall prevention mechanism, and FIGS. 4A to 4E show the movement of the fall prevention mechanism with the opening operation of the ADF device over time. .

The drop prevention mechanism includes a rotary shaft 133, a pair of abutted members (rotating members) 135 fixed to both ends of the rotary shaft 133, and each abutted member 135 in the direction of arrow B (FIG. 5
), And a fall prevention member 137. The rotating shaft 133 is mounted on the mounting table 1.
3 and is rotatably supported. The contact member 135 contacts at least one contact member 136 provided on the frame portion on the upper surface of the image forming apparatus main body shown in FIGS. As shown in FIG.
The abutted member 135 is formed in a loose arc shape at the lowermost portion in contact with the abutting member 136. When the ADF device 1b is rotated from the horizontal position to the upper open position, as shown in FIG. The top rotation is performed from the state shown to the state shown in a. More specifically, the contact member 136 includes a flat portion whose upper surface is parallel to the upper surface of the image forming apparatus main body, and an inclined portion which is gently inclined downward. When the ADF device 1b is closed on the upper surface of the device main body 1a, the contact member 136, the contacted portion 135 of the fall prevention mechanism, and the fall prevention member 137 have a positional relationship as shown in FIG. 4E. At this time, the fall prevention member 13
Numeral 7 denotes a recessed storage section 201 provided on the mounting table 13 so as not to hinder the conveyance of the original.
Transfer mechanism 14 (Figs. 3 and 5)
It is preferable that it is comprised so that it may be accommodated inside. Therefore, the fall prevention member 137 is hidden by the lower roller 14X when the document is in the horizontal position for transporting the document, and the document is
It is discharged by 4Z, 14X. And the mounting table 13
Starts rotating upward, the contacted member 135 is gradually moved in the direction of arrow B shown in FIG.
It rotates smoothly in a state of contacting the inclined portion on the upper surface of the contact member 136. The rotation of the rotating member 13
3 rotates in the direction of arrow B, and the fall prevention member 137 fixed coaxially by the rotation of the rotation shaft 133 also moves in the direction of arrow B.
Rotate in the direction.

Then, the fall prevention member 137 is
1 and is protruded from the state of being housed inside 1 to a working position acting on the document. As shown in FIG. 3, the drop prevention member 137 is provided with a bending portion that abuts on the lower end side of the original when the mounting table 13 is located at the open position, that is, the upstream end side in the transport direction and supports the original. ing. Therefore, the mounting table 1
When the cover 3 is opened, the bent portion can prevent the document from dropping from the end of the mounting table 13. Next, the mounting table 1
In the state in which 3 is closed from the open position to the horizontal position, the contacted member 135 and the fall prevention member 137 are sequentially moved from the state shown in FIG. Rotate. That is, the contact member 136 on the apparatus main body side
The lower part of the contacted member 135 contacts the upper surface of the
Pivots against the biasing force of. As described above, since the contact member 136 is provided with a gentle slope on the upper surface thereof, the arc portion shelled at the lower part of the contact member 135 is smoothly rotated along the slope. To go. Then, as the contacted member 135 rotates, the rotating shaft 133 to which the contacted member is fixed also rotates. As a result, the fall prevention member 137 rotates and is stored in the storage portion 201, and the fall prevention member 137 does not hinder the document discharge.

Although the contact member in the present embodiment has a shape including a flat portion and an inclined portion, the shape of the contact member is not particularly limited to this. The shape may be a gentle arc or a semicircle, as long as the rotation of the contacted member is performed smoothly and appropriately. Further, the contact member may also serve as a position regulating member for maintaining a gap for appropriately transporting the document between the upper surface of the apparatus main body 1a and the ADF apparatus 1b. Also, the document placing unit 14 is linked to the rotation operation of the fall prevention mechanism on the placing table 13 side.
A rotation shaft provided with a fall prevention member may also be provided on the fourth side, and a configuration may be adopted in which the fall of the document before image reading can be prevented with the rotation of the mounting table. In the present invention, the transfer paper discharge unit 7 for discharging the transfer paper is provided in the image forming apparatus main body as an embodiment. However, a transfer paper transport path that can be transported toward the upper part of the apparatus is separately provided. If the ADF device is not currently in use and the detection sensor detects that no document is loaded on both the loading table 13 and the document loading section 144, the loading table 13 or the document loading section The transfer paper may be discharged onto the 144 by a user's selection. In this case, it is easy and convenient to take out the transfer paper and visually check the state.

[0020]

As described above, according to the present invention, a fall prevention mechanism which can reliably prevent the sheet member from falling with a simpler structure is provided. An improved and highly reliable device can be provided at low cost. In addition, since the opening and closing mechanism that can open and close only the sheet mounting table is provided, the burden on the user during opening and closing can be reduced, and the life of the opening and closing mechanism itself can be extended.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an image forming apparatus having a fall prevention mechanism according to an embodiment of the present invention and a sheet conveying device to which the mechanism is applied.

FIG. 2 is an internal configuration diagram of an image forming apparatus having the sheet conveying device shown in FIG.

FIG. 3 is a side view showing an opening / closing operation of a sheet mounting table in the sheet conveying apparatus shown in FIG.

FIG. 4 is an operation diagram of a fall prevention member according to the present invention.

FIG. 5 is a perspective view of a main part showing a configuration of a fall prevention mechanism according to the present invention.

FIG. 6 is a side view for illustrating a rotation operation of the fall prevention mechanism according to the present invention.

FIG. 7 illustrates an image forming apparatus provided with a sheet conveying device according to the related art of the present invention.

[Description of Signs] 1a: Image Forming Apparatus Main Body 1b: ADF Device 13: Placement Table 14: Transport Mechanism 144: Document Placement Unit 17: Document Discharge Unit 131: Support 133: Rotating Axis 134: Spring 135: Contact Member 136: Contact member 137: Fall prevention member 200: Document 201: Concave storage section

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 2

[Correction method] Change

[Correction contents]

FIG. 2

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

Claims (5)

[Claims] A mounting table for mounting a sheet member provided on an upper portion of a main body of the image forming apparatus; a conveying means for conveying the sheet member; In the sheet member transport device having a connecting means for coupling, when the mounting table is in the horizontal position for transporting the sheet member, retracts so as not to obstruct the sheet member, and when the mounting table is in the open position where the mounting table is opened, A sheet member transporting mechanism having a sheet drop prevention mechanism for projecting from the upper end of the loading table in accordance with the rotation operation when the mounting table is rotated from a horizontal position and preventing the sheet member from falling in the direction of the transporting means; apparatus. And a rotation member provided at a connection end of the mounting table with the transfer means, the rotation member being in contact with a contact member provided on an upper surface of the image forming apparatus main body, and being rotated. ,
An urging means for applying an urging force to the rotating member in a direction opposite to a rotating direction; a drop preventing means rotated to a prevention position and a non-prevention position with the rotation of the rotating member; 3. The sheet member conveying device according to claim 2, further comprising a support shaft that coaxially supports the moving member and the fall prevention unit. 3. An abutment member provided at an upper portion of the main body of the image forming apparatus is provided at a position other than an image reading means provided at an upper portion of the main body of the image forming apparatus. 3. The fall prevention mechanism according to claim 2, further comprising: a contact portion provided to contact the pivoted member; and an inclined portion for urging the pivotable operation of the pivoted member. 4. An end portion on the connection side of the transfer means with the mounting table, wherein the pivoting operation of the drop prevention means to a non-operating position is allowed, and when the mounting table is in the closed position. 4. The fall prevention mechanism according to claim 3, further comprising a storage section for storing said fall prevention means. 5. A feeding means for feeding a sheet member mounted on the sheet mounting table to an image reading mechanism provided on an upper surface of the image forming apparatus main body, the sheet member conveying mechanism comprising:
5. The sheet member conveying device according to claim 4, further comprising a discharge unit that discharges the sheet member on which an image is formed by the image forming apparatus main body onto a sheet mounting table.